Introduction: Graphics and Principles of Data Visualisation

Seminar: Data Visualisation: Principles, Practices and Applications


Julia Schulte-Cloos

University of Marburg


December 1, 2025

✉️ julia.schulte-cloos@uni-marburg.de

Welcome

What makes a good graph?

01_Graphics

What makes for a good data visualisation?

Please note up to five key characteristics that make for a good data visualisation.

Overview of the workshop

Overview

1️⃣ Why Data Visualization?


2️⃣️ Foundations of the Grammar of Graphics


3️⃣️ Hands on - Fundamentals of ggplot


4️⃣ Advanced Visualizations


5️⃣ Hands on - Advanced ggplot applications

Learning Outcomes


What can you expect to get out of this workshop?



At the end of the workshop, you will be able to…:

  • Understand the principles of data visualization and best practices
  • Comprehend the grammar of graphics for creating structured visualizations
  • Apply the principles of ggplot to design effective data visualizations
  • Readily create both simple and advanced visualizations
  • Develop visualizations that incorporate maps and geospatial data
  • Enhance your graphs and visualizations with advanced styling and textual elements
  • Design interactive visualizations to engage your audience

Why visualizations?

any effort to help people understand the significance of data by placing it in a visual context

  • to explore your own data
    • exploratory analysis
    • outlier detection
  • to communicate and report
    • …clearly (using good design principles)
    • …precisely and accurately (a plot is worth 1000 words)
    • …effectively and efficiently
  • purpose: convey information and make a point (Wilke 2019)
  • …data rarely speaks for itself
  • to represent results of statistical analyses

Types of variables in data visualization scenarios

Wilke 2019 (Fundamentals of Data Visualisation)

Application 1

Try to analyze the famous visualization by Hans Rosling (“Gapminder”) together with your neighbor. Please click on the link to enlarge.

[1] The “Why” (Purpose): What is the main story this graph is trying to tell?

[2] The “What” (Data): What data variables can you identify in the plot?

[3] The “How” (Mapping): How does the graph use visual properties to represent these variables?

05:00

Application 2

Try to analyze this datajournalism visualization from the German newspaper Die ZEIT together with your neighbor.

[1] The “Why” (Purpose): What is the main story this graph is trying to tell?

[2] The “What” (Data): What data variables can you identify in the plot?

[3] The “How” (Mapping): How does the graph use visual properties to represent these variables?

05:00

A few great people working on ggplot2 and data visualisation

➡️ workshop material heavily draws on their excellent workshops and practical materials

Questions? 🙋 🙋‍♂️

Thanks for your attention.

References

Wilke, Claus O. 2019. Fundamentals of Data Visualization: A Primer on Making Informative and Compelling Figures. O’Reilly Media.